1. Field of the Invention
The present invention relates to an axial fan and a frame thereof.
2. Description of the Related Art
Recently, in conjunction with the improvement in performance of electronic apparatuses, the amount of heat generated from electronic components located in an enclosure of an electronic apparatus goes on increasing. In addition, the size of an enclosure is decreased through the years, so that the density of the electronic components to be arranged in the enclosure also goes on increasing. In such an electronic apparatus, an axial fan is used for cooling and ventilating the inside of the electronic apparatus. In order to improve the cooling characteristics of the axial fan, it is required to increase the rotation speed of an impeller of the axial fan.
The impeller is rotationally driven by a motor. As the rotation speed of the motor is increased, the vibration caused by the rotation is also increased. Accordingly, in order to rotate the motor at a high speed, it is necessary to reduce the vibration or to provide a damping structure. The reduction of vibration can be realized by reducing an unbalance in a rotor section of the motor. For example, in the production of an axial fan, in order to reduce the unbalance, a plurality of components are incorporated. However, in the production of the axial fan, the number of adjusting processes is increased, and the number of processes for managing and assembling the components, so that the productivity may disadvantageously be deteriorated. Thus, it is necessary to improve the vibration characteristics of the axial fan without increasing the number of components.